Switch-handle



G. B1. THOMAS.

SWITCH. HANDLE.

APPLICATION FILED Novv.2a.19Is.

353,675., mamas@ 21,1920.

I OFI 1:4mm/vica',` GEORG E B. Thum@ 51 GEGRGE B. THOMAS, 0F BRIDGEPORT,CONNECTICT, ASSIG-NOR TCTHE BRYANT ELEC- TRIO COMPANY, OF BRIDGEPORT,CONNECTICUT, .A CORPORATION 0F CONNECTICUT.

A SWITCH-HANDLE.

To all whom z't Imay con-cem `Be it known that I, GEORGE B. THOMAS, acitizen of the United States of America, residing at Bridgeport in thecounty of Fairfield and State of Connecticut, have invented certain newand useful Improvements in Switch-Handles, of which the following is aspecification.

Mv invention relates to switch handles, and .particularly to handlesIfor rotary snap switches, the object of my invention being to provide ahandle of such construction that while it is attached to theswitchspindle by a screw thread connection, it 1s not possible tounscrew the handle by rotating it in reverse direction. l

In the accompanying drawings- Figure 1 is a broken side elevation of arotary snap switch to which a handle embodying my invention in one formis at-y tached-the handle being shown 1n a position of partialreverserotation;

Fig. 2 isa sectionbn the line 2-2 Fig. l; and l Fig. 3 is a droppedperspective of certain of the handle elements.

The switch illustrated is. of the usual rotary snap type comprising aninsulating base 5 upon which the switch mechanism is mounted and housedwithin a sheet metal cover 6 resting on the base. The switch f spindle 7is provided at its upper end with a threaded boss 8 of reduced diameter,on which the tapped lower end of the stem 9 of the switch handle isscrewed. The body of the switch handle consists of an insulating thumbpiece 10 centrally pierced by a rectangular well 11, which, at the outerend of the handle, is continued by a cylindrical opening 12 of lessdiameter, while at its inner end the well is shouldered to afl'ord aseat 13 lfrom which extend opposite bays 14 Jfor a purpose hereinafterexplained.

Fast on the stem 9 of the handle is a washer 15, having oiset lugs 16which serve as dogs to engage the ratchet faces 17 of a rectan lardriving nut 18. .The latter is slipped.Ll upon the outer end of the stemand is engaged by the walls of the rectangular well 11 so as to rotatewith the switch handle 10. A light coil spring 19 bears at its lower endagainst the driving nut 18, to maintain the latter in operative relationto the dogs 16 of the washer 15. The upper end of this spring bearsagainst a rectangu- Spec'ication of Letters Patent. Patented. Sept. 21.,i920. Application led November 28, 1919. Serial No. 341,042.

lar Washer 20 seated against the upper end of the well 11, but piercedat 21 -to permit tlie reduced end 22 of the stem 9 to pass therethrough.A shoulder` 23 limits the downward movement of'the Washer on the stem.The outer end of the stem is slotted at 24 to receive a screw driver, bywhich the switch handle maybe turned' on the switch spindle 7 in reversedirection to remove it. I`he driving nut 18 is preferably recessed onits upper face to aiiord a spacin lHange 25, which prevents the spring19 groinl being compressed sufficiently. to render the parts rigid withrelation to each other, in case the washer20 by accident slips over theshoulder 23.

' Below the flange 15 on the switch stem is arranged a bushing 260irectangular shape, having a cylindrical neck 27 which bears against andsupports the flange 15. This bushing is maintained within the lthumbpiece 10 by'a washer 28 resting against the seat 13 at the inner end ofthe handle and having wings 29 which are sprung into the bays 14, abovementioned, and serve to maintain 'the stem and its associated parts inpermanent engagement with the thumb' piece. -Below the washer 28 is aspring 30 and a bearing washer 31, the latter resting upon the ferrule32 at the mouth of the boss 33 on the 4switch cover 6, and serving tohold the latter in position on the base 5 in the assembled position ofthe parts.l

The operation of the device is as follows: The switch handle elementshavin been assembled as shown in Fig. 1, thei screwed upon the threadedboss 8 of the ,switch spindle 7 by the usual clockwise rotation.Obviously the stem 9 is rotated with the switch handle in this directionby rea.- son of the engagement of the dogs 16 with the ratchet shoulder17 of the driving nut 18 in the rectangular recess 11 of' the handle. Toactuate the switch the handle is turned further in the same direction.Upon reverse or counter-clockwise rotation of the handle, however, thedrivin nut 18 rides over the ratchet dogs 16 without rotating thestem-9, since thev spring 19 is intentionally made soclight that thefrictional drag between the ratchet elements is quite insufficient toloosen the screw connection between the switch spindle and the stem ofthe thumb piece. If the operator should press 'down the thumb piece inan attempt to compress andle is l the spring 19 sufliciently` torenderthe parts rigid with relation to each other, he isv halted by theengagement of the-washer\20 on the narrow shoulder 23 of the stem'm9.This shoulder is intentionally made of sueh'slight width that therictional engagement between the washer 20 and the shoulder isinsuicient to overcome the resistance afforded by the threadedconnection between the switch spindle and the-stem of the thumbI piece.If, on the contrary, the handle is pulled outward in order tosecure arigid engagement between the sleeve 27 of the bushlng 26 and the Washer15 on the switch stem, it is `still. impossible to render the partssuiiciently rigid with relation to each other to unscrew the stem sincethe sleeve 27 is intentionally made so thin that its end bearing surfaceis very much reduced, and

this fact, coupled with the fact that it bears against only a small areaof the washer 15, so reduces the frictional engagement between the partsthat it also is insuiiicient to overcome the resistance offered by thethreaded connection between the stem 9 and the switch spindle. By reasonof the fact f that the washer 20, bushing 26, and nut 18 arerectangular, as well as by reason of the fact that the washer 28 closelyengages the switch handle, it is impossible to tilt the latter withrelation to the switch stem suiiiciently to cramp the parts in this waysuiiiciently to nullify the action of the ratchet. The only way in whichthe switch handle can be removed from the switch spindle is byunscrewing the stem 9 with a screw driver, or slmilar instrument,through the opening` 12, and directly engaging the slit end of the stem.Accidental removal of the handle is thus prevented.

Various modifications in details of construction, which do not departfrom what l claim as my invention, will readily occur to those skilledin the art. Moreover, while l have shown a construction which operatesin the manner described without the use of any lubricant between theparts, the desired action is made still more certain if a suitablelubricant is applied to the'coperating bearing surfaces.

inserted assente y A handle for rotary snap switches comprlslng a thumbpiece recessed to form a well non-.circular in cross' section, a stemarranged 1n said well, a ratchet element fast onsaidstem, a coperatingratchet element .freely mounted kgn said stem, but engaged in sald well,a spring for maintaining said ratchet elements in cooperating position,'and means on said stem accessible from the outer end of the Switchhandle for rotating said stem, together with screw means at the oppositeend of said stem fom connecting \the handle to the spindle of the switchop- ,erated thereby. t

2. rotary switch handle comprising a centrally apertured thumb piece, astem arranged therein, a ratchet element fast on said switch stem, acooperating-ratchet element free on said stem, but engaged in said well,a spring for pressing said free ratchet element into engagement with theratchet element on the stem, and a bearing for the opposite end of saidsprin together with a shoulder on said stem limiting the endwisemovement ot said bearing on the stem to prevent undue compression of thespring.

3. A rotary snap switch handle comprising a thumb piece centrallyrecessed, a stem arranged in said recess, a flange fast on said stem, abushing engaging said flange, a washer engaging the switch handle andmaintaining said bushing interposed between the same and the iiange onthe switch stem, together with means at the switch end GERGE B. THOMAS.

